Extraction of helium-3 gas from ilmenite ore utilizing radiant solar energy

ABSTRACT

A method and apparatus for the recovery of Helium3 (He-3) from ilmenite ore (iron titanate or FeTiO3), including recovery from the surface and near surface of a satellite such as the Moon, and extraction using solar energy and the natural rotational cycles of the satellite for the purpose of obtaining the He-3 for use in nuclear reactors for generation of pollution-free electrical power for commercial or industrial uses, as a fuel to propel space vehicles, and for other purposes, such as medical use.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No. 60/205,450, filed May 19, 2000, entitled “Method of Extraction Of Helium-3 Gas From Ilmenite Ore Utilizing Radiant Solar Energy.”

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to the recovery of Helium-3 from ilmenite (iron titanate or FeTiO3) ore, and more particularly to a method of recovering Helium-3 from ilmenite ore located on or near the surface of the moon, for the purpose of using the Helium-3 in nuclear reactors for generation of pollution-free electrical power for commercial or industrial uses, for use as a fuel to propel space vehicles, and for other purposes.

[0004] 2. Description of the Prior Art

[0005] By the year 2050AD mankind may have run out of all of the economically recoverable fossil fuels, such as oil, coal, and natural gas. There may also be no place to put the toxic residues of present nuclear fission reactors. West Valley, N.Y. no longer wants such waste and neither does Nevada. Worse yet, in 2050AD all of the alternate sources of energy, such as hydroelectric, wind, wood, tidal, geothermal and solar, will not supply even 25 percent of the estimated energy that will be needed to feed the Earth's projected population.

[0006] Present day nuclear fission reactors operate like a slow atomic (“A”) bomb, splitting heavy plutonium or uranium atoms into smaller elements and giving off power. American and Russian nuclear engineers and physicists have succeeded in slowing down the fission reaction to produce useful power, as exemplified by Three-Mile Island and Chernobyl (clearly a mixed blessing!). Others have accomplished this more successfully. France generates a significant part of its energy requirements from fission reactors and has achieved a perfect safety record. Their reactors are all of the same design and are run by nuclear engineers. The United States builds its fission reactors all differently and mostly leaves the actual operation of the reactors to technicians. But France still has the same problem with disposal of the toxic residues.

[0007] Mankind may have no alternative but to develop the ability to harness useful energy from nuclear fusion. To date, it has not been feasible to produce a controlled, sustainable nuclear fusion reaction, at least not to the point of producing useful power. However, progress is being made in this area. Nuclear fusion reactors operate like a slow hydrogen (“H”) bomb, fusing light weight atoms such as hydrogen or helium. Present nuclear fusion reactors are classified by the method used to support the nuclear fusion reaction, which takes place at a temperature much hotter than the surface of the Sun. No vessel or container on Earth can hold such a reaction. Hence, the reaction must be suspended by either electromagnetic, gravitational (inertial), or electrostatic fields.

[0008] The TOKAMAK at Princeton N.J. operates by magnetic confinement in a huge 250-ton water-cooled electromagnet. The electromagnet exquisitely controls and shapes a magnetic field that physically supports the reaction. The TOKAMAK has never operated longer than a few seconds at a time and the federal government has withdrawn its support.

[0009] With inertial confinement, hundreds of powerful lasers are pointed concentrically at a gold capsule containing a small amount of hydrogen. The pressure and the temperature of the capsule are raised to fusion levels, producing a burst of energy. This process must then be repeated, perhaps 100 times per second, to provide a reasonably continuous flow of power. Two such reactors exist in the USA, one in Rochester N.Y. and one in Livermore Calif. As far as known, neither has ever approached a “break-even” point in power generation.

[0010] With electrostatic confinement, the fusion reaction is confined by electrostatic forces within a large potential well that is centrally located within a vacuum chamber. The potential well may be provided by a spherical grid that is highly negatively charged to act a physical anode, or by confining electrons using a quasi-spherical-cusp magnetic field to form a highly negatively charged virtual anode. Dr. Gerald Kulzinski and co-investigators at the Fusion Technology Institute at the University of Wisconsin/Madison have successfully demonstrated a fusion reaction using electrostatic confinement (a spherical grid anode is used) and positive ions of deuterium (D) and helium-3 (He-3 or ³He) as the reaction fuel. The ions are inserted into the vacuum chamber and fall through the large potential well created by the anode. Within the anode's strong electrostatic field, the ions oscillate backward and forward at increasing speed until fusion occurs. Because a mixture of D and He-3 ions is introduced into the vacuum chamber, both a D-D fusion reaction and a D-³H fusion reaction occur, producing a steady stream of neutrons, protons, electrons, helium-4 (He-4), tritium, gamma and x-rays. It has been postulated that if He-3 ions alone could be introduced into the vacuum chamber, and if a large enough potential well could be generated (i.e., −200 kV), a ³H-³H fusion reaction would occur, producing He-4 and two protons that come off at very high energies. The beauty of the ³H-³H reaction is that the fuel (He-3) is non-radioactive, the process is non-radioactive, and the residue (He-4) is non-radioactive. In fact, the residue, He-4, is used to inflate childrens' balloons. Thus, He-3 may be the perfect fuel for fusion-based nuclear power generation.

[0011] Another He-3 application would be space travel. Rocket scientists agree that mankind has about reached the limit of human ability to travel in space using chemical rockets. To achieve anything near the speed of light we will need a new energy source and a new propellant. Nuclear fission is not an option, but nuclear fusion of light weight elements such as He-3 would permit more nearly approaching the speed of light.

[0012] Additional uses for He-3 may also be imagined. Indeed, history has repeatedly shown that when a new method or material becomes available, new uses for it arise. He-3 is no exception. It is only recently that reports have emerged from Thomas Daniel at the University of Virginia Health center and from other sources, of the use of He-3 to greatly augment the utility of ions in the Magnetic Resonance Imaging (MRI) procedure in visualizing lung lesions. The patient breathes a few breaths of He-3 that has been super-polarized by laser irradiation as the patient breathes it. The gas holds this polarization for a few seconds and the resulting polar response is many times more effective than that of the normal water response that the MRI usually sees. This permits visualization of lung lesions down to a resolution of 1 mm. When gasses are “hyperpolarized,” it means a large quantity of the atomic nuclei's “spin”—a magnetic property of quantum particles—point in the same direction. The hyperpolarized gasses provide an MRI signal that is about 100,000 times stronger than the signal produced by water, the substance that is normally visualized by MRI scans, according to Dr. Daniel.

[0013] Physicists Gordon Cates and William Happer at Princeton University, along with Mitchell Albert of Brigham and Womens' Hospital in Boston, are primarily credited with the idea of using polarized gasses for medical imaging. Unfortunately, the present cost of the He-3 (about $400/liter) rules it out for routine clinical use and much effort is directed to use of the less effective, but cheaper, xenon gas for this purpose. Certainly the availability of reasonably priced He-3 would encourage more research into other possible uses.

[0014] The primary disadvantage of He-3 is that there is not much of this material available on Earth. It comes up to the Earth's surface as a tiny percentage of natural gas. There is also a small additional supply of He-3 in old nuclear weapons in the form of radioactive tritium gas (H-3), which decays into, of all things, He-3 in about 13 years (half-life). Thus, there may be enough He-3 here on Earth to build one big earth-bound reactor and one small orbiting reactor. Beyond that, mankind must find another source of He-3. One very promising source is the Earth's moon.

[0015] He-3 comes from the Sun in an ionized form on the solar wind. The ions hit the Earth's magnetic field and get diverted away. Because the ions cannot land on Earth, they drift around and eventually land on the Moon. They have been landing there for four billion years. It is estimated that there is more He-3 energy on the Moon than the Earth has ever had in the form of fossil fuels. In particular, it is believed that there is sufficient He-3 available on Earth's moon to supply the energy needs of Earth for approximately one thousand years. After that it may be possible to collect the He-3 from Mars or other planets and their moons.

[0016] He-3 on the Moon is contained in an ore called ilmenite (iron titanate), that contains titanium dioxide. He-3 comes adsorbed on the titanium dioxide (TiO₂). The ilmenite must be scraped off the lunar surface and refined to obtain the titanium dioxide. It is said that heating the titanium dioxide to 7000 Celsius will release the adsorbed He-3.

[0017] In an article entitled “Fusion Power From Lunar Resources” by Kulcinski and Schmitt, Fusion Technology, Vol. 21, p. 2221-2229 (July 1992), a proposal is made to mine ilmenite ore on the lunar surface using a lunar mining vehicle. The principle of the miner operation is that sunlight is relayed from stationary mirrors to the slowly moving miners to heat the ore and power the miner during the lunar day (14 Earth days). The released gases, which include He-4 and He-3, are collected in tanks, which are then transported back to a mining base camp. During the lunar night, the gaseous mixture is exposed to the “coldness” of space, and all the components except He-4 and He-3 are condensed. The He-3 is thereafter separated from the He-4 by “superleak” techniques, which are said to be well known on Earth.

[0018] A disadvantage of the foregoing He-3 mining proposal is that the miner is required to both mine ilmenite ore and process the He-3 therefrom. A relatively complicated mirroring arrangement is required to heat the ore and power the miners, presumably after the minors have finished mining and are placed at a fixed location. Insofar as the miners are mobile, they will be relatively small, and the amount of He-3 gas they can generate and hold will be limited. Finally, whatever He-3 gas they do generate needs to be offloaded for condensation at a remote processing location.

SUMMARY OF THE INVENTION

[0019] The foregoing problems are solved and an advance in the art is provided by a novel method for extracting Helium-3 gas from ilmenite ore using direct radiant solar energy. In accordance with the present invention, there is provided a method of recovering Helium-3 from titanium dioxide, including the steps of: collecting a quantity of titanium dioxide having He-3 adsorbed therein, placing the titanium dioxide having adsorbed He-3 in a solar collector, heating the titanium dioxide in the solar collector within an optically transparent collection vessel to a temperature of at least about 123 degrees Celsius to drive off the He-3 in a gaseous form, cooling the vaporized He-3 so as liquefy the He-3; and recovering and storing the liquefied He-3 into a suitable container. The invention further contemplates an apparatus for recovering He-3 from titanium dioxide, including a rotating satellite, a mining apparatus for collecting a quantity of titanium dioxide having He-3 adsorbed therein, a solar collector (which may be parabolic in shape) operatively associated with the satellite and suitable for receiving the titanium dioxide, the solar collector heating the titanium dioxide to a temperature of at least about 123 degrees Celsius to drive off the He-3 in a gaseous form when the satellite and associated solar collector are oriented so as to directly receive concentrated radiation from the sun, an optically transparent collection vessel surrounding the solar collector for collecting the He-3 driven off by the heat of the solar collector, the collection vessel being adapted to allow the vaporized He-3 to cool as the satellite rotates causing the solar collector to be shaded from direct radiation from the sun, wherein the collection vessel further includes a system for concentrating and liquefying the He-3 and a system for collecting and storing the liquefied He-3 in a suitable container.

[0020] It is therefore an object of the invention is to utilize radiant solar energy for He-3 extraction.

[0021] A further object of the invention is to concentrate the normal solar radiant energy using parabolic solar reflectors so as to achieve a higher temperature of the titanium dioxide to facilitate the boiling off of He-3 gas.

[0022] A further object of the invention is to utilize the normal, very low ambient temperature of the lunar environment during the lunar night to facilitate the liquefication of the He-3 gas.

[0023] A further object of the invention is to liquefy the resulting He-3 to facilitate its transport to nuclear fusion reactor sites.

[0024] A further object of the invention is to provide a reasonably cheap source of rocket fuel at the sight of rocket refueling (the Moon) to facilitate space travel from a space station on the Moon.

[0025] A further object of the invention is to provide a suitable rocket fuel at reasonable cost to permit accelerating rockets closer to the speed of light, which cannot be accomplished by chemical rockets.

[0026] A further object of the invention is to provide a fuel that does not produce greenhouse gasses as a by-product of power generation.

[0027] A further object of this invention is to provide fuel for a power generation in system which is not subject to the limitation in efficiency (usually about 40%) of the Carnot cycle for a heat engine. He-3 power generation is an entirely electrical reaction, like a fuel cell, and thus its efficiency is not limited by the Carnot cycle.

[0028] Yet another object of the invention is to provide methods and apparatus suitable for use on other planetary bodies (e.g., Mars) or satellites thereof, in which the present invention may present a viable source of fuel for a galactic space exploration and/or colony.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The foregoing and other objects, features and advantages of the invention will become apparent in the accompanying description when read in view of the drawings in which:

[0030]FIG. 1 is a perspective view of exemplary containment vessel shown on the surface of a satellite in accordance with an embodiment of the present invention;

[0031]FIG. 2 is a perspective view of a focusing, parabolic solar collector used in accordance with an embodiment of the present invention; and

[0032]FIG. 3 is a flow diagram showing the process employed by an embodiment of the present invention superimposed on a lunar time line.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0033] The present invention will now be described in connection with a preferred embodiment. However, it will be understood that there is no intent to limit the invention to the embodiment described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

[0034] For a general understanding of the present invention, reference will be made to the drawings wherein like reference numerals have been used throughout to designate identical elements. Thus, referring to FIG. 1, there is shown a representation of a plastic or similarly transparent containment or collection vessel 30. As depicted, the collection vessel 30 may be constructed as a geodesic dome or similar hoop-shaped (semi-cylindrical) design so as to enable full access to the direct solar radiation when the collection vessel is in direct, sunlight 40. The collection vessel 30 is preferably vacuum-tight, and may be entered or accessed via one or more resealable openings therein (not shown) for the purpose of “charging” the system with ilmenite ore, and extracting the products subsequent to processing. The collection vessel 30 thus also contains the titanium dioxide that is extracted from the ilmenite ore. In a preferred embodiment, the collection vessel 30 is operatively affixed to the surface 36 of a terrestrial satellite such as Earth's moon, and may be relocated to different ore/mining locations.

[0035] Referring also to FIG. 2, within the collection vessel 30 are one or more parabolic or similar concentrating solar reflectors or collectors 50 having a conveyor 60 or similar transport mechanism for moving the ilmenite ore 70 therethrough in the direction of arrow 80. The solar collectors 50 are designed to receive the direct solar radiation 40 and concentrate or focus it at the location of the ore in order to magnify the effect of the Sun's solar radiant energy and “boil-off” the He-3, which will be retained within the collection vessel 30. Although the solar collectors 50 may not be needed at certain lunar latitudes (i.e., where there is sufficient intensity of the Sun's solar radiation energy at the site of the lunar refinery), they are preferred.

[0036] Referring now to FIG. 3, there is depicted a flowchart illustrating the process steps in accordance with one embodiment of the present invention. He-3 can be extracted from ilmenite ore at a temperature of between about 200 degrees Celsius and 1000 degrees Celsius. It is believed that extraction by direct solar radiation, enhanced by the solar collectors 50, is best accomplished at a temperature somewhere between these extremes, for example, at about 700 degrees Celsius. The solar radiation extraction of He-3 from titanium dioxide (which may also be previously refined from the raw ilmenite ore) would follow these same patterns. At step 100, the refining process/system is “charged,” whereby the ilmenite ore, or perhaps titanium dioxide already recovered therefrom, is placed within the collection vessel 30, above the reflecting solar collectors 50, if present.

[0037] Subsequently, the satellite rotates into direct sunlight (beginning of lunar day), and is held there for approximately two weeks, as the Moon rotates toward the Sun in step 110. The titanium dioxide will become very hot and the He-3 will boil off. The mean daytime temperature on the Moon is 107 degrees Celsius and the maximum temperature is 123 degrees Celsius. With the solar collectors 50, a temperature of 1000 degrees Celsius could be obtained that would boil off 100% of the He-3, but reduced fractions could be retrieved at a lower temperature, including temperatures as low as 123 degrees Celsius.

[0038] After approximately two Earth weeks, the Moon rotates away from the Sun and step 120 begins. This will result in very cold temperatures within the collection vessel 30 (e.g., minus 153 degrees Celsius mean temperature and minus 232 degrees Celsius minimum temperature), which would go a long way toward liquefying the He-3. However, as further indicated by step 120, although He-3 liquefication will be promoted by virtue of the collection vessel 30 being exposed to the lunar night, it is believed that additional cooling will be necessary to complete the liquefication and compression of the He-3. Accordingly, as shown in FIG. 1, a cooling unit 90 may be associated with the collection vessel 30 by placing the cooling unit therein, or by locating the cooling unit 90 remotely from the collection vessel and providing an He-3 transport line therebetween. After the He-3 is completely liquefied and compressed according to step 120, it is retrieved and stored in step 130 for subsequent transport to Earth as liquid He-3, e.g., via a space shuttle. As shown in FIG. 1, a containment vessel 95 that is operatively connected to the cooling unit 90 may be used for this purpose.

[0039] It is estimated that single shuttle load (25 tons) of liquid He-3 brought back from the Moon could supply all of the energy needs of the United States for a year. The cost of the He-3, including the shuttle, the Moon colony, and the ilmenite refinery, amortized over a suitable number of decades, has been calculated to be an equivalent oil cost of about $8 per equivalent barrel of oil. Today, a barrel of oil cost about $22!

[0040] Note, moreover, that most of the “greenhouse gasses” which contribute to global warming on the Earth are carbon dioxide from the combustion of fossil fuels. The generation of power from He-3 completely eliminates this source of pollution from our planet.

[0041] An additional benefit of Moon-based He-3 mining is that the refining process, in addition to producing He-3, will produce by-products of water, carbon, nitrogen, oxygen and other elements needed to make a manned Moon-colony self-sustaining. Having little atmosphere or gravity, a Moon-colony should then be an ideal space station from which to launch further space exploration. It would be very attractive to refuel space ships where the fuel is located, rather than transporting the fuel to a space station.

[0042] Of course, it will be appreciated that the Moon is not the only satellite capable of producing He-3 according to the above-described method. Earth's planetary neighbors, such as Mars, may also be suitable sites for He-3 recovery. On the other hand, should political or economic conditions preclude some of these manufacturing/refining operations on the Moon, Mars or other terrestrial bodies, the subject invention may still be applicable in desert areas of Earth or on other satellites.

[0043] Accordingly, a method and apparatus have been disclosed for the recovery of He-3 from ilmenite ore, and more particularly from ilmenite ore located on the surface and near surface of the Moon or other satellite. The He-3 may be used in nuclear reactors for generation of pollution-free electrical power for commercial or industrial uses, for use as a fuel to propel space vehicles, and for other purposes such as medical use.

[0044] The techniques described herein are advantageous because they are efficient and simple compared to other approaches proposed for the mining and refining of He-3 from ilmenite. The system, while ideal for a lunar-based operation, can be adapted to any number of satellite configurations. In addition, it can be used to generate and collect by-products that may be important for extended stay or exploration of space. The techniques of the invention are further advantageous because they utilize readily implementable technology and the inherent rotation of satellites to provide a range of alternatives, each of which is useful in appropriate situations. As a result of the invention, it is now possible to economically collect and refine ilmenite ore to produce He-3 and other useful by-products.

[0045] Although the invention has been described in conjunction with preferred embodiments thereof, it should be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art. The invention is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. 

What is claimed is:
 1. A method of recovering Helium-3 (He-3) from titanium dioxide, including the steps of: collecting a quantity of titanium dioxide having He-3 adsorbed therewith; placing the titanium dioxide having adsorbed He-3 in an optically transparent collection vessel; placing said collection vessel at a location where direct solar radiation will be received at said solar collector; heating the titanium dioxide to a temperature of at least about 123 degrees Celsius to drive off the He-3 in a gaseous form; and cooling the vaporized He-3 within said collection vessel by shading it from solar radiation so as to promote liquefication of the He-3.
 2. The method of claim 1, wherein said titanium dioxide is collected by obtaining a quantity of ilmenite ore (FeTiO3) having titanium dioxide therein and placing said ore in said collection vessel.
 3. The method of claim 2, wherein said ilmenite ore is placed on a conveyor for heating said titanium dioxide within said collection vessel.
 4. The method of claim 1, wherein said titanium dioxide is collected by extracting it from ilmenite ore (FeTiO3) and placing said titanium dioxide in said collection vessel.
 5. The method of claim 1, wherein said titanium dioxide is heated by a solar collector disposed within said collection vessel.
 6. The method of claim 1, wherein said step of shading said collection vessel is performed by placing said collection vessel on a rotating satellite.
 7. The method of claim 6, wherein the recited steps are repeated on a schedule determined by the rotational cycle of said satellite.
 8. The method of claim 7, wherein said satellite is the moon of Earth.
 9. The method of claim 7, wherein said satellite is Earth.
 10. The method of claim 7, wherein said satellite is the planet Mars.
 11. The method of claim 1, further including the step of further cooling the He-3 as required to complete liquefication and compression thereof.
 12. The method of claim 1, further including the step of collecting and storing the liquefied He-3 into a suitable container.
 13. An apparatus for recovering Helium-3 (He-3) from titanium dioxide, including: a solar collector suitable for receiving ilmenite ore (FeTiO3) containing titanium dioxide with He-3 adsorbed therein, said solar collector being adapted to heat the titanium dioxide to a temperature of at least about 123 degrees Celsius to drive off the He-3 in a gaseous form when said solar collector is oriented so as to directly receive radiation from the sun; and an optically transparent collection vessel surrounding said solar collector for collecting the He-3 driven off by the heat of said solar collector, said collection vessel being adapted to allow the vaporized He-3 to cool when said solar collector becomes shaded from direct radiation from the sun.
 14. The apparatus of claim 13, wherein said solar collector comprises a reflector.
 15. The apparatus of claim 13, wherein said solar collector comprises a parabolic reflector.
 16. The apparatus of claim 13, further including a conveyor for conveying the ilmenite ore through said solar collector.
 17. The apparatus of claim 13, wherein said collection vessel is vacuum tight, and includes at least one resealable opening for introducing the ilmenite ore into said collection vessel.
 18. The apparatus of claim 13, further including a cooling unit for concentrating and liquefying the He-3.
 19. The apparatus of claim 13, further including a container for collecting and storing the liquefied He-3 for transport.
 20. A system for recovering Helium-3 (He-3) from titanium dioxide, including: a rotating satellite; a solar collector, operatively associated with the satellite, and suitable for receiving ilmenite ore (FeTiO3) containing titanium dioxide with He-3 adsorbed therein, said solar collector being adapted to heat the titanium dioxide to a temperature of at least 123 degrees Celsius to drive off the He-3 in a gaseous form when the satellite and associated solar collector are oriented so as to directly receive radiation from the sun; an optically transparent collection vessel surrounding said solar collector for collecting the He-3 driven off by the heat of said solar collector, said collection vessel being adapted to allow the vaporized He-3 to cool as the satellite rotates causing said solar collector to be shaded from direct radiation from the sun; a cooling unit associated with said collection vessel for concentrating and liquefying the He-3; and a container for collecting and storing the liquefied He-3 for transport from said satellite. 